Visit the Aurecon Bridge Building Competition website for more information and the confirmed dates for the Judging Day at various locations.

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1 Guidelines Overview Welcome to the Aurecon Bridge Building Competition. Once again, Aurecon will have an optional digital component to reflect the increasing role virtual/online environments and programmes play in the engineering and testing of bridges. As with previous years, schools will still have the opportunity to physically construct a bridge from the kit of materials provided to them and the Judging Days will run as usual i.e. the bridges will be judged for efficiency, strength, and innovation. In addition, and as a way for students to better plan and design their bridges, all schools will also have the option to design their bridges digitally via SketchUp Make or SketchUp Free. Both SketchUp programmes are free for schools to use. SketchUp Make is a desktop version that can be downloaded to your computer, and SketchUp Free is based on a web browser. Teams have the option to submit their digital wireframes to Aurecon to compete for a new Digital Award for the best virtual bridge design. To be eligible for the Digital Award, teams must: Use the digital tool, SketchUp Make or SketchUp Free. For further information please see section 4.2 of this document Submit their digital wireframe designs to Aurecon by 11.59pm on Monday 2 July 2018 Submit a physically constructed bridge at your location s Judging Day in accordance with these guidelines Visit the Aurecon Bridge Building Competition website for more information and the confirmed dates for the Judging Day at various locations. 2 The brief As a team, your goal is to design and construct a bridge to transport the goods. Sustainable, innovative and economical designs are some of Aurecon s main priorities, and it is important to Aurecon that this is incorporated in your design. While it is only optional to use the digital tool, SketchUp Make or SketchUp Free, to plan and design your bridge, we strongly recommend that you do. We are looking for a variety of bridge designs that are able to showcase efficiency, strength, and creativity. 3 Specifications 3.1 Bridge specifications It is greatly encouraged to plan and design your bridge digitally in SketchUp Make or SketchUp Free before you begin building it. This will ensure you don t run out of materials, that your design is structurally sound, and that you are eligible to compete for the Digital Award. If you prefer to not compete for the Digital Award and simply just construct your bridge, you will still be eligible for all other awards on Judging Day. pg. 1

2 Your bridge must be built within certain specifications outlined below. In order to apply the testing load cell, a purpose built rig will be used. Please refer to Figures 1 4 to see the rig and bridge dimensions, and Figures 5 10 for examples of building techniques with the materials, and bridge examples Span Your bridge must have a total length of 700mm in order to span across the clear 650mm chasm between the supports of the testing rig. Take into account that your bridge will be resting on the testing support frame (refer to point A on Figure 1) End supports The width of your supports at each end is 25mm (refer to point B on Figure 1). Your bridge cannot rely on the testing support frame for lateral support. Side thrusts onto the vertical faces of the frame is not permitted Width Your bridge must be no wider than 140mm (refer to point C on Figure 2) Depth The maximum allowable depth of the bridge below the load bars when placed in the loading position is 180mm (point D Figure 1) Load bar clearance A clear opening for the two load bars must be accommodated in your bridge design. Two areas at least 20mm high, 50mm wide and 30mm apart, are required to place the load bars on the bridge deck area. The load bars and hanger assembly must be able to fit within the central region of the bridge span, not at the ends of the span (refer to point F on Figure 1). The load bars should be able to be placed no more than 200mm below the supports to allow the load cell and test weight to be put into position (refer to point G on Figure 1) Road and car Your bridge will be required to allow a small vehicle to pass through. It is not essential to have a deck, however you must make provision for an 80mm wide roadway to be placed along your bridge with a total clearance height of 40mm. A 30mm wide x 35mm high vehicle will be passed through along the bridge (refer to Figure 4). Important: The position and direction of the Bridge when the road and car is tested as per above, must be the same position and direction of how the bridge is placed on the testing rigs to be load tested. pg. 2

3 Figure 1 pg. 3

4 Figure 2 pg. 4

5 Figure 3 Figure 4 CAR & ROADWAY 80mm ~40mm 35mm 5mm 80mm 4 Bridge building kit, tools and safety 4.1 Kit contents Your bridge building kit will contain the following items. Everything listed may be used on your bridge: 8 balsa wood sticks (6.5mm x 6.5mm x 580mm) 8 balsa wood sticks (6.5mm x 6.5mm x 330mm) 1 cardboard tube (see important note below on how this is to be used) (60mm diameter x 600mm) pg. 5

6 1 tube of PVA glue (125ml) 1 piece of 5m long string Important: The cardboard tube must not be used in its original form and must be cut into smaller pieces, such as flat, curved or small cylindrical pieces. The end caps may be used. 4.2 SketchUp tools for Digital Award To compete for the Digital Award, teams must a SketchUp Make or SketchUp Free (.skp) file of the bridge s wireframe to Eloise.Febbraio@aurecongroup.com by 11.59pm Monday 2 July Both SketchUp programmes are free for schools to use. SketchUp Make is a desktop version that can be downloaded to your computer, while SketchUp Free is based on a web browser. Click to view and/or download software for: SketchUp Make SketchUp Free Important: Both programmes are free for all educators and schools to use, and does not require a license. As part of downloading SketchUp Make you may receive a free trial of SketchUp Pro for 30 days. You may wish to design your bridge using the SketchUp Pro trial, however no points will be given for creating your design to scale. Teams must not under any circumstances use sketches from the SketchUp 3D warehouse. For more information, and to view a tutorial video on how to use SketchUp, visit the Aurecon Bridge Building Competition website. 4.3 Extra equipment Aurecon recommends using the following extra equipment to construct your bridge: Safety goggles and gloves A printed copy of your digital bridge design you created in SketchUp Pencils and paper for planning and drawing bridge before it is constructed A tape measure and a ruler A small hacksaw or Stanley knife for cutting the balsa wood and cardboard tube Clothes pegs or bulldog clips for temporarily holding the balsa wood together whilst glue is drying Sandpaper for finishing edges for a better build quality pg. 6

7 4.4 Decorating your bridge Colouring in marker pen, spray or water based paint can be used to decorate your bridge. Acrylic paints, additional glue, or surface finishing coatings are not permitted. Please note to always apply coating in a well-ventilated area. 4.5 Safety precautions Safety is very important at Aurecon. We recommend the following steps to ensure your safety: All construction and decoration work must be supervised by a teacher at all times Wear safety goggles and gloves while creating your bridge Ensure workplace is well ventilated at all times, especially while gluing and decorating When working with sharp tools, cut on a clean, flat, and stable surface Read and carefully observe all glue instructions included in your kit Protect the surfaces you will be working on from glue and accidental cutting 5 Judging and testing 5.1 Judging On Judging Day, your team(s) will be called before a panel of judges consisting of Aurecon engineers and/or guest judges who will engage in discussion with the team about the approaches and techniques used in your bridge design. The judges will assess your bridges in the following categories: Workmanship (5 pts) Joints with good contact between members Robust feel Innovation (5 pts) Aesthetics (5 pts) Compliance with dimension requirements Member size correspond to force flow path Structural form Efficiency in force flow path Creative techniques at joints Use of building techniques (e.g. post-tensioning of string, beam types, etc.) Visual appeal Proportion Neat finish Functionality (5 pts) Ability to support a roadway Ability to pass traffic across the bridge Smoothness of traffic flow along the roadway pg. 7

8 Important: As per above, the position and direction of the bridge when the road and car is tested, must be the same position and direction of how the bridge is placed on the testing rigs to be load tested. The total formula of the design score is: Design Score (20) = Workmanship + Innovation + Aesthetics + Functionality 5.2 Testing Your physical bridge will be tested in the bridge testing zone at the Judging Day events. Bridges are tested by progressively increasing the load on the hanger attached to the bridge. Your bridge is considered to have failed if any member or joint breaks or the bridge fails to carry any additional load. The load will be recorded in the judging spreadsheet. On the day, you will be required to wear safety goggles provided by Aurecon. Aurecon engineers will be conducting the testing. Important: While we take all steps to test all of the bridges on Judging Day, if a bridge is non-compliant with the rules of this competition in any way, it cannot be eligible for any of the prizes. Please check with the specifications outlined in section 3.1 to ensure it can be tested. The most common mistake made by teams is constructing a bridge that is not long enough to fit on the testing rigs. If this happens, we are unable to test the bridge at all. Digital component testing Expert engineers from Aurecon will pick out the three best (per location) digital bridge SketchUp wireframe designs that have been submitted to Eloise.Febbraio@aurecongroup.com by 11.59pm on Monday 2 July. Then, prior to the Judging Days, the Aurecon engineers will virtually test the top three and will look to predict where the bridges will fail and the approximate weight each can support. The top three digitally designed bridges will be showcased and virtually tested on a projector at the Judging Days events. The digital testing of the projects will be compared and contrasted with the testing of the physical bridge on the rig. Important: The top three digitally designed and consequent virtual testing results will be kept confidential until Judging Day. The winner of the Digital Award will be announced at prize giving at the end of the day. 6 Scoring The design score is the total of the judges score (20 points), this will be added to the efficiency score, which is determined by the ratio between the mass supported by the bridge and the weight of the bridge itself. The formula used to determine the total score is: Total score = Design Score (20) + mass supported by bridge (kg) self weight of bridge (g) Award categories Based on your team s bridge design, you can take home one of the following award titles. These will be awarded on the day of the event based on your team s performance All-Rounder Award The All-Rounder Award is won by teams with the highest combined score (strength-to-weight and judges score) as detailed above. Winners will receive: $1000 prize to school pg. 8

9 $100 each to students Efficiency Award The efficiency award is given to the team whose bridge design has the best strength-to-weight ratio, that is, the maximum amount of weight it can carry/support without collapsing compared to the weight of the structure. Winners will receive: $500 prize to school $50 each to students Strength Award The Strength Award is offered to teams whose bridges reach the maximum mass recorded on the day. Winners will receive: $500 prize to school $50 each to students Innovation Award The Innovation Award will be assigned by the judging panel on the day of the competition. This is a combination of creativity and innovation how do you stand out from the crowd? Winners will receive: $500 prize to school $50 each to students Digital Award Teams can submit the digital wireframe design of their bridge drafted in SketchUp Make or SketchUp Free to Eloise.Febbraio@aurecongroup.com by 11.59pm on Monday 2 July. After the bridge wireframes have been submitted, Aurecon will select the three best SketchUp bridge wireframe designs per location and will virtually test these using bridge analysis programmes to determine which bridge supports the highest load. The winning students of the Digital Award will receive: $50 each to students 7 Construction tips To ensure you have the best chance of success, we recommend the following: Pay attention to the joints between the timber elements. This is critical to the bridge achieving its capacity. Bridges most often fail here because of lack of glue or inadequate contact between the two surfaces. Think about the forces in each member. Will it be in tension or compression? In other words, are the members being stretched or crushed? Picture how the bridge will deflect (refer to Figure 5) this will help you visualise the forces in the members. Long members in compression have a tendency to buckle. A member that is long will buckle and therefore fail more easily than a short member of the same cross section. Carefully push on both ends of a plastic 30cm ruler and see how it bends as you apply force. Now get a friend to gently support the centre of the ruler with a finger on both sides, and again carefully push on the pg. 9

10 ends of the ruler. Notice how the ruler resists more force. If you have long compression members in your bridge, consider reducing their unsupported lengths by connecting them to cross members or bracing (refer to Figure 6). A member that is in tension will most likely fail at its joints. Think about where the maximum forces are going to be applied, and how this might affect your construction method. Remember all of the pieces provided are shorter than the distance the bridge needs to span. Think about the most efficient use of the materials supplied. The aim is to use all of the materials provided in your bridge design. Decide how you want to use the cardboard. It could be used in sheet form as part of beams, or as sheet bracing for stability. Refer to Figures 7 10 for possible ideas. If you use the string to supplement the strength of balsa wood tension members, try tensioning the string. Untensioned string adds no benefit. You can tension the string by gently applying a compression force to your tension members while fixing the string in place until the glue dries. Remember to only apply a force to your members once they have already been glued in position. Failure at supports is common due to the shear forces present. Your design needs particular attention in these areas to make them strong and stable. The ability to resist shear forces depends on the amount of material used. Two pieces of balsa wood will have twice the strength to resist shear force than a single piece. Be as accurate as possible keeping symmetry about the longitudinal axis of the bridge (parallel to the direction of the span). This will help the bridge load evenly, and prevent twisting of the bridge as well as assisting in maintaining stability. To see bridges from previous years, visit our website, Don t forget to take visual appeal, workmanship and creativity into account when designing and constructing your bridge points will be awarded for these three categories. Have a good hard look at the bridge ideas presented in Figures pg. 10

11 Figure 5 pg. 11

12 Figure 6 pg. 12

13 Figure 7 GIRDER BRIDGE pg. 13

14 Figure 8 pg. 14

15 Figure 9 pg. 15

16 Figure 10 pg. 16

17 8 Glossary The following terms are referenced in the guidelines: Word Definition 1. Beam A member that resists loads by bending. 2. Bracing A structural member used to stabilise or stiffen a framework. 3. Buckle The bending, warping, or collapse under a force. It occurs when compression overcomes an object s ability to endure that force. 4. Capacity The maximum amount that something can contain/take. 5. Compression Compression is a force which squeezes objects together. 6. Cross-Section A 2D perception of the internal arrangement of a 3D object. 7. Deflection The movemenet of a structure or structural part as a result of stress. 8. Force Flow Path The path an external force takes to reach the supports through your structure. 9. Joints A connection point, in this instance, the joint is at the glue to timber member interface. 10. Lateral support A type of support to help prevent sideways movement. 11. Member An element that forms part of any structure or bridge, such as a beam, bracing or a support. 12. Shear A force which slips two surfaces away from each other. 13. Span The clear distance between the support points 14.Tension Tension is the force that stretches or pulls objects apart. pg. 17